Generally, launch vehicles comprise a booster stage, an upper stage, and a primary payload. The booster stage provides the initial boost towards orbit, and the upper stage is often employed to carry the primary payload to a further desired orbit or to achieve escape velocity. An example of a booster stage and upper stage combination is the Atlas V launch vehicle and the Centaur upper stage manufactured by either the United Launch Alliance (ULA), the assignee of the instant application, or the Lockheed Martin Corporation. Other launch vehicles also employ upper stages, such as the Delta II and the Delta IV launch systems manufactured by either the ULA or the Boeing Corporation.
An interstage adapter commonly is utilized to structurally interconnect the booster stage and the upper stage, and a payload adapter commonly is utilized to structurally interconnect the upper stage and the primary payload. The various stages and adapters typically are aligned along a common longitudinal axis of the launch vehicle and are designed to withstand launch loads. An example of an interstage adapter is the ISA-400 Interstage Adapter manufactured by Ruag Space. Examples of payload adapters include a C-adapter and an Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter (ESPA).
Typical launch vehicles have unused space, for example, the space between various stages. In an effort to exploit this unused space, payload adapters have been designed and positioned in the unused space to transport additional payloads, i.e., secondary payloads, to space. The secondary payloads share the launch costs with the primary payload and have little to no impact on the primary payload's mission. In this way, the launch costs may be distributed among the various payloads, thereby reducing the cost attributable to the primary payload as well as the secondary payloads.
Providing sufficient power to meet the requirements of the secondary and/or tertiary payload mission(s) is an existing problem in the art. Generally, the secondary and/or tertiary payloads are powered by batteries and/or solar panels. As can be appreciated, batteries have a limited life whereas regenerative power sources, such as solar power, are readily available. The use and effectiveness of solar panels has been limited, however, because of the large size and volume required by the solar panels to provide the spacecraft adequate power for the mission. Typically, solar panels have been stowed external to the adapters and deployed transverse to the adapters in a standard wing fashion. However, for payload adapters disposed and transported within a payload fairing, the volume available for externally mounted solar panels is limited to the space between the payload adapter and the fairing internal envelope, which can be further limited by the presence of secondary payloads also mounted external to the payload adapter. Further, solar panels cannot be mounted externally to a payload fairing or to interstage adapters due to exposure to the harsh launch environment. None of the launch systems currently in existence or otherwise known to those of skill in the art address the aforementioned problems.